We have done this - our environment is quite vanilla. We use Payroll for North America but not Absence Mgmt or Time & Labour. The ability to load external data was awesome and it worked pretty much as expected (and required). The biggest learning for our team was creating the custom rtf. template for the 'printable' statement. Our compensation team had some very specific graphing requirements, but we were able to deliver successfully by using PeopleBooks as a guide.

There is a bug with Canadian taxes that is supposed to be fixed in bundle 11. If you are a Canadian company let me know and I will share our work around.